XML 76 R64.htm IDEA: XBRL DOCUMENT
v3.25.2

Regulatory & Capital Matters - Dividend Restrictions and Deferrals (Details) $ in Millions | 6 Months Ended
--- | ---
Jun. 30, 2025 USD ($)
Dividend Restrictions and Deferrals |
Number of previous years retained profit considered for dividend payment | 2 years
Payments of dividends | $ 118.0
Minimum capital requirements, minimum percentage required | 2.50%

X
- References No definition available. + Details
Name: | osbc_DividendRestrictionsAndDeferralsAbstract
Namespace Prefix: | osbc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of previous years retained profits combined with the current years profits used to determine the amount of dividends that may be paid in any calendar year. + References No definition available. + Details
Name: | osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit
Namespace Prefix: | osbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The minimum percentage of Tier 1 Common Capital required to be maintained in the next fiscal year following the latest fiscal year to prevent capital distribution limitations under regulatory capital rules. + References No definition available. + Details
Name: | osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths
Namespace Prefix: | osbc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of dividends that can be declared or paid without affecting the banking or savings institution's regulatory capital position. + References No definition available. + Details
Name: | us-gaap_AmountAvailableForDividendDistributionWithoutAffectingCapitalAdequacyRequirements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant